The present invention relates to a reading technique in a semiconductor memory device having a plurality of memory blocks.
In a memory device having two or more memory blocks, the access speed can be increased by sequentially reading out data from the memory blocks to a single output node. In order to read out data in sequence from the memory blocks, the output of the memory blocks is switched. The switching is controlled by a read signal.
Where the output is switched, there is a possibility of outputting data from the memory blocks at the same time caused by the difference in a transmission time delay of the read out signals. If this happens, a pass current flows through the memory blocks. The pass current causing such a malfunction that destroys the contents stored in the memory blocks. Efforts made to restrain the influences exerted by the pass current have been imposing a restriction in achieving higher access speed.